The invention is based on an anti-freezing device for preventing the freezing of pipe sections disposed outdoors or in temporarily undercooled rooms, filled with water of a certain overpressure and forming a flow path for the water, particularly in the area of fittings in accordance with the type of the main claim.
It is known in the art to protect water pipe sections against freezing in areas which are subject to freezing in that heating coils or other heating equipment are mounted directly on the water pipes. Heat insulation can also be installed. The insulation may make accessing the pipes more difficult or even impossible because the fittings must not lead to the outside, and heating equipment usually is very expensive in terms of production and installation and it is disadvantageous because of a continuous energy consumption. Also, the heating coils known in the art, for example, do not provide adequate frost protection in the area of watering troughs for horses or other fittings if only the water supplying pipe sections are heated. For this reason, plastic stoppers are provided, for example, in many watering troughs for horses in the area of the fittings which are subject to freezing. The stoppers are designed to break open at the overpressure occurring when the water freezes so as to prevent the watering trough from bursting. In practical application, however, it was found that said plastic stoppers are unable to ensure adequate protection against frost damage. Another disadvantage is that when the plastic stopper breaks open a permanent leak will develop through which water from the pipe can flow out uncontrollably.
In order to prevent frost damage on pipes it was previously proposed to install suitable pressure control valves. Such a pressure control valve has a valve seat which is in communication with the pipe section to be monitored and which interacts with a movable valve body so as to seal the pipe section, where the valve body is prestressed in a closed position in such a way that the pressure control valve is closed when the overpressure is normal and that it opens when the pressure increases as a result of the water freezing so as to drain a water quantity from the pipe section. Because theoretically, the pipe or the like will start freezing from the inside of the pipe close to the wall in the direction to the central pipe axis it was proposed in the German patent DE 827 629 or in the U.S. Pat. No. 4,776,362, for example, to dispose the pressure control valve partially on the inside of the pipe such that the part of the valve containing the valve seat is shifted inward away from the inside surface of the pipe wall or the like. This is intended to achieve that the area of the valve seat is still disposed in warmer, flowing water near the pipe axis when the freezing begins with the related increase in pressure so as to prevent the valve from freezing and to allow fluid to drain through the pressure control valve. One disadvantage of the above solutions is that the valve parts mounted on the inside of the pipe create obstacles for the flow which impair both the free flow through the pipe sections in normal operation and they also create places favoring deposits which could gradually affect a pipe and thus make it unusable.
Compared to the above, the anti-freezing device of the invention having the characteristic features of claim 1 has the advantage that the flow through the monitored pipe section is not hampered or impaired by parts of the anti-freezing device.
This is achieved in that the valve seat is disposed at a distance from the flow path outside the flow path in a branch which is in continuous communication with the pipe section. Surprisingly, it was found that the function of such anti-freezing devices is reliably ensured although the area of the valve seat, contrary to the theories of the above prior art, is not in the axial range of the flow path to be monitored. Using a branch on the monitored pipe section also offers advantages with regard to the freedom of the spatial arrangement of the pressure control valve relative to the monitored pipe or the fittings. Tests have shown that freezing can be reliably prevented by means of the invention to xe2x88x9215xc2x0 C. The use of the invention is not limited to watering troughs for animals, such as horses, cattle, hogs or the like where pipe sections and/or fittings are frequently located in areas which are subject to freezing as a result of increasingly keeping the animals outdoors again. The invention is also able to reliably solve anti-freezing problems in the field of water supply for mobile homes and the like, on campgrounds, in gardens, garages, etc.
According to an advantageous embodiment of the invention the branch is or can be substantially oriented vertically so as to support the discharge of the water caused by the freezing-related overpressure by means of gravity.
According to a further embodiment of the invention the branch has a front side opposite the monitored pipe section and the pressure control valve is or can be disposed on the front side of the branch. This can facilitate the installation and allows largely straight flow paths which support the flow.
An embodiment of the invention provides for the branch to be oriented transversely, preferably substantially vertical to the flow path of the pipe water, where the branch is preferably provided on a tee which can be installed in the pipe section. The installation of such a tee in the area of the pipes which is subject to freezing allows retrofitting of existing pipes with the pressure control valves of the invention without significant effort.
According to another embodiment, the pipe section has two partial sections which are preferably oriented at right angles relative to each other so as to form an angled flow path and the branch is disposed substantially so as to lengthen a partial section, preferably the inlet-side partial section. This allows the water flowing into the pipe section to reach the valve opening of the pressure control valve substantially without changing the direction of flow, thereby allowing particularly favorable flow conditions for the fluid flowing out at times of frost danger. In particular, subsequently following warmer water is able to flow particularly rapidly into the area which is subject to freezing so as to protect it against freezing.
In a particularly preferred embodiment the monitored pipe section is provided in a basic fitting body of a watering trough for animals, particularly a watering trough for cattle or horses, and the pressure control valve is configured so as to screw into a threaded bore of the fitting body which is in communication with the pipe section. This allows, in a very simple manner, the use of the threaded bores for receiving the above described plastic stopper which are provided on most watering troughs for animals, particularly watering troughs for horses, so as to cost-effectively mount an anti-freezing device of the invention without any structural changes in the fittings, even in previously installed watering troughs or the like.
In an advantageous embodiment, the closing pressure of the valve body is, preferably continuously, adjustable. This makes it particularly easy to adapt the anti-freezing device to the normal water pressure prevailing at the installation site. This is particularly advantageous for watering systems having a number of cattle or horse watering troughs or the like which are installed at a distance from each other on a supply line because the water pressures prevailing at the installation site of the individual watering troughs can differ considerably. The adjustment can be made separately for each valve, for example in that the pressure control valve remains just closed at ambient temperatures of approx. 5 to approx. 30xc2x0 C. and then automatically opens slightly and temporarily when the temperature drops toward the freezing point.
A particularly simple design of the anti-freezing device is obtained with a preferred embodiment in that the pressure control valve has a cylindrical, shell-like valve housing in which a valve body, which is preferably configured as a plunger, spring-loaded by means of a pressure spring, is guided so as to move. The valve housing preferably has a connecting sleeve at its top end and at its bottom end an axial thread for an adjusting screw engaging therein on which the pressure spring is supported, which on the other side pushes against the underside of the valve body opposite the valve seat. In closed valve position, the valve body can seal discharge openings provided in the valve housing relative to the connecting sleeve and in open position release them or connect them with the monitored pipe section, respectively.
In a preferred embodiment, the connecting sleeve has an external thread allowing the pressure control valve to be mounted in a simple manner, particularly without soldering or welding, for example in the above described receiving bore for the plastic anti-freezing stopper or at a front end of a branch, which is provided with an internal thread, on a tee or also in a suitably dimensioned threaded bore in a wall of a pipe, fitting or container. The branch can be formed partially or substantially completely by the connecting sleeve which is preferably configured in one piece with the valve housing.
The shell-like valve housing can be manufactured very easily of metal, such as brass, or of plastic, particularly POM, which allows holding the production costs very low. The outside contour can be substantially circular cylindrical, but if required, it can also have a hexagonal configuration, at least in sections, so as to allow the pressure control valve to be screwed in comfortably by means of a suitable wrench or a pipe wrench or the like. If required, the installation can also be achieved without any tools, i.e. manually. In this case, an at least sectionally non-circular, for example hexagonal outside contour is also advantageous.
For a better sealing of the valve body, particularly the plunger, relative to the inside wall of the valve housing, the plunger is preferably provided with at least one O-ring or a toroidal sealing ring.
The valve seat in the valve housing can be formed by a toroidal sealing ring or an O-ring against which the valve body rests, for example with its front surface or a conical ring surface in the closed position of the valve.
Instead of the O-ring another sealing ring having the respective sealing properties can also be used. Instead of a uniaxial rotationally symmetrical valve body having at least in sections a circular cylindrical or conical surface area the valve body can also be a ball, particularly of rubber.
According to an embodiment of the invention, above the sealing contact between the valve body and the inside housing wall, particularly above the O-ring disposed on the surface area of the valve body or the plunger, respectively, one or more discharge openings are provided in the wall of the valve housing, which can be configured particularly simply as bores. When the anti-freezing device opens its valve the water can flow out of the area which is subject to freezing via the discharge openings so as to prevent freezing as a result of the flow movement. The seal on the plunger then prevents water from entering the space of the valve housing containing the pressure spring where it could possibly impair the function of the valve as a result of freezing.